BalsaUSA Stingray40
The Balsa USA Stingray is a very nice airplane. One of our club members has one. Powered with an OS52-4stroke. It flys like a dream. If you put an OS .61 in it will be a rocket. We fly at 5000' ASL and the .52 is plenty of power. At sea level or up to about 2000' I think you will find a 46FX or a newer .50 engine plenty of power.